The Effect of Gaseous Ozone Generated by Surface Dielectric Barrier Discharge on the Decay and Quality of Stored Onion Bulbs

Junghyun Lim,Seungmin Ryu,Sangheum Eom,Jung Woo Yoon,Jong-Seok Song,Sang-Hye Ji,Seong Bong Kim

doi:10.3390/agronomy11061058

Junghyun Lim, Seungmin Ryu + Show 5 more

Open Access

https://doi.org/10.3390/agronomy11061058

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Abstract

An effective and eco-friendly technology is needed to prevent postharvest loss of onion bulbs during cold storage. This study investigated the effect of gaseous ozone on the decay and quality of onion bulbs during storage at 2 °C and 70% relative humidity for two months. Gaseous ozone was adjusted to a concentration of 1.27 ± 0.024 ppm in the storage room by generating a high voltage discharge in air. After two months of storage, gaseous ozone significantly reduced the counts of aerobic bacteria (e.g., Rahnella aquatilis) and fungi (e.g., yeast and mold) in the onion bulbs by 4 log (CFU g−1) and 0.92 log (CFU g−1) compared with those of an untreated control, respectively. The microbial reduction by gaseous ozone resulted in a lower rotten rate of the onion bulbs, which was less than 20.0% compared with that of the untreated control. Moreover, the ozone exposure extended the storage life of the onion bulbs by delaying its color change and softening during storage. Our results suggest that gaseous ozone can control the decay of onion bulbs safely during storage.

Highlights

It was previously reported that gram-negative Pseudomonas aeruginosa and gram-positive Enterococcus faecalis showed susceptibility to gaseous ozone due to weak cell walls compared with the fungus Candida albicans [28]
R. aquatilis, which was dominant in the onion bulbs, was reduced reported that Gram-negative Pseudomonas aeruginosa and Gram-positive Enterococcus fa calis showed susceptibility to gaseous ozone due to weak cell walls compared with t fungus Candida albicans [28]
The results of this study indicate that the ozone treatment can be used to reduce the

Summary

Introduction

Onion bulbs are commonly stored at low temperature to ensure their good quality during storage [1]. A high concentration of gaseous ozone is effective for microbial decontamination without quality loss of the fruit when shortly applied during short-term storage [14,15,16]. A low concentration of ozone treatment is reported to effectively control postharvest diseases of fruits and vegetables when continuously applied during long-term storage [17,18,19]. This study evaluated the effect of continuous ozone on the decay and qualozone treatment has been extensively studied for the preservation of fruits and vegetables, ity offew onion bulbs storage. Considering different responses postharvest crops to ozone, it is necessary to confirm ozone can control decay of soluble onion bulbs with good safety during storage.

Microbial Analysis

Onion Quality Assessments

Statistical Analysis

Ozone Reduced the Total Counts of Bacteria and Fungi in the Onion Bulbs

Ozone Did Not Affect the Weight Loss and Sugar Content of the Onion Bulb

Conclusions